Setting XMP is not guaranteed, although likely. Lots depend on the IMC of the chip.
I don't know of a single person that has not been able to run 3600Mhz XMP RAM on a Ryzen 3000 system. This is why 3,600Mhz is offered. If it was a lottery whether your silicon could run 1800 FCLK then OcUK would not offer a 3,600Mhz kit and stick to offering 3,200Mhz.